[PATCH 1/2] gianfar: Deal with link state changes during GFAR_RESETTING dev state

From: Thomas Graziadei
Date: Mon Feb 13 2017 - 08:09:33 EST


From: Thomas Graziadei <thomas.graziadei@xxxxxxxxxxxxxxxxx>

The link state is not correctly set in the case that the network driver
is reconfigured while the link state changes. The phy informs the gianfar
driver, but gfar_update_link_state just exits and therefore looses the
change event. The network driver remains in the old state until a new link
event is sent.

A trace log from a possible scenario at bootup, when the link state in the
network driver stays down even though the phy reports an up link. The test
sends a SIOCSHWTSTAMP ioctl at the right moment (which calls reset_gfar):
ip-1196 [000] 5.389270: phy_start: state: READY -> UP
kworker/0:2-1195 [000] 5.389784: phy_start_aneg: state: UP -> AN
kworker/0:2-1195 [000] 5.389788: phy_state_machine: state: UP -> AN
kworker/0:2-1195 [000] 6.828064: adjust_link: eth0, link 0 -> 0
kworker/0:2-1195 [000] 6.828599: phy_state_machine: state: AN -> NOLINK
test-1470 [000] 7.460422: reset_gfar: before locking GFAR_RESETTING
test-1470 [000] 7.470806: phy_stop: state: NOLINK -> HALTED
test-1470 [000] 7.478806: phy_start: state: HALTED -> RESUMING
kworker/0:2-1195 [000] 7.479478: adjust_link: eth0, link 0 -> 1
kworker/0:2-1195 [000] 7.479482: phy_state_machine: state: RESUMING -> RUNNING
test-1470 [000] 7.479826: reset_gfar: after locking GFAR_RESETTING

To resolve the issue adjust_link is called after every GFAR_RESETTING lock
section. Adjust_link itself checks if anything has changed and updates the
link accordingly.

Signed-off-by: Thomas Graziadei <thomas.graziadei@xxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/freescale/gianfar.c | 7 +++++++
drivers/net/ethernet/freescale/gianfar_ethtool.c | 15 +++++++++++++++
2 files changed, 22 insertions(+)

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 957bfc2..b3b5c43 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2617,6 +2617,10 @@ static int gfar_change_mtu(struct net_device *dev, int new_mtu)

clear_bit_unlock(GFAR_RESETTING, &priv->state);

+ // catch maybe missed link state changes
+ if (dev->flags & IFF_UP)
+ adjust_link(dev);
+
return 0;
}

@@ -2631,6 +2635,9 @@ void reset_gfar(struct net_device *ndev)
startup_gfar(ndev);

clear_bit_unlock(GFAR_RESETTING, &priv->state);
+
+ // catch maybe missed link state changes
+ adjust_link(ndev);
}

/* gfar_reset_task gets scheduled when a packet has not been
diff --git a/drivers/net/ethernet/freescale/gianfar_ethtool.c b/drivers/net/ethernet/freescale/gianfar_ethtool.c
index a93e019..065f05e 100644
--- a/drivers/net/ethernet/freescale/gianfar_ethtool.c
+++ b/drivers/net/ethernet/freescale/gianfar_ethtool.c
@@ -330,6 +330,7 @@ static int gfar_scoalesce(struct net_device *dev,
struct ethtool_coalesce *cvals)
{
struct gfar_private *priv = netdev_priv(dev);
+ struct phy_device *phydev = dev->phydev;
int i, err = 0;

if (!(priv->device_flags & FSL_GIANFAR_DEV_HAS_COALESCE))
@@ -408,6 +409,10 @@ static int gfar_scoalesce(struct net_device *dev,

clear_bit_unlock(GFAR_RESETTING, &priv->state);

+ // catch maybe missed link state changes
+ if (dev->flags & IFF_UP)
+ phydev->adjust_link(dev);
+
return err;
}

@@ -445,6 +450,7 @@ static int gfar_sringparam(struct net_device *dev,
struct ethtool_ringparam *rvals)
{
struct gfar_private *priv = netdev_priv(dev);
+ struct phy_device *phydev = dev->phydev;
int err = 0, i;

if (rvals->rx_pending > GFAR_RX_MAX_RING_SIZE)
@@ -482,6 +488,10 @@ static int gfar_sringparam(struct net_device *dev,

clear_bit_unlock(GFAR_RESETTING, &priv->state);

+ // catch maybe missed link state changes
+ if (dev->flags & IFF_UP)
+ phydev->adjust_link(dev);
+
return err;
}

@@ -569,6 +579,7 @@ int gfar_set_features(struct net_device *dev, netdev_features_t features)
{
netdev_features_t changed = dev->features ^ features;
struct gfar_private *priv = netdev_priv(dev);
+ struct phy_device *phydev = dev->phydev;
int err = 0;

if (!(changed & (NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX |
@@ -590,6 +601,10 @@ int gfar_set_features(struct net_device *dev, netdev_features_t features)

clear_bit_unlock(GFAR_RESETTING, &priv->state);

+ // catch maybe missed link state changes
+ if (dev->flags & IFF_UP)
+ phydev->adjust_link(dev);
+
return err;
}

--
2.7.4